Various techniques have been used for many years for the surgical treatment of spinal fractures. These technique have included laminectomy and various plate and screw procedures. U.S. Pat. No. 4,401,112 to REZAIAN describes an expandable spinal fixator which is essentially a turnbuckle mounted between upper and lower bearing members, each of which essentially is a pedestal which rests on and engages the opposing surfaces of the vertebrae between which it is placed. Although, the device permits extension of the fixator once it is in place, its inherent lateral instability makes it necessary for the device to be further anchored by brackets which are stapled to the spinal vertebrae. Further, the type of turnbuckle employed in the patented device severely limits the extent of extension which is possible once the device is in place between the vertebrae. Additional extension, once the device is anchored by the supporting plates, then becomes impossible unless these plates are first disengaged from the vertebrae to which they are stapled.
Particularly in view of the dire consequences which attach to any lateral slippage or movement in spinal fixators and the need which often arises for greater expansion and separation between the vertebrae, a purpose of the present invention is to provide an improved spinal fixator which can both be securely anchored between the vertebrae so that lateral movement or slippage is virtually eliminated and which can be extended to a greater extent than has heretofore been possible using devices of the prior art and subsequently removed the following completion and recovery from prosthesis.